Lewis Structure of SF5- (With 5 Simple Steps to Draw!)

Lewis Structure of SF5-

I’m super excited to teach you the lewis structure of SF5- ion in just 5 simple steps.

Infact, I’ve also given the step-by-step images for drawing the lewis dot structure of SF5- ion.

So, if you are ready to go with these 5 simple steps, then let’s dive right into it!

Lewis structure of SF5- ion contains five single bonds between the Sulfur (S) atom and each Fluorine (F) atom. The Sulfur atom (S) is at the center and it is surrounded by 5 Fluorine atoms (F). The Sulfur atom has 1 lone pair while all the five Fluorine atoms have 3 lone pairs. The Sulfur atom has -1 formal charge.

Let’s draw and understand this lewis dot structure step by step.

(Note: Take a pen and paper with you and try to draw this lewis structure along with me. I am sure you will definitely learn how to draw lewis structure of SF5- ion).

5 Steps to Draw the Lewis Structure of SF5- ion

Step #1: Calculate the total number of valence electrons

Here, the given ion is SF5- ion. In order to draw the lewis structure of SF5-, first of all you have to find the total number of valence electrons present in the SF5- ion.
(Valence electrons are the number of electrons present in the outermost shell of an atom).

So, let’s calculate this first.

Calculation of valence electrons in SF5- ion

  • For Sulfur:

Sulfur is a group 16 element on the periodic table.

Hence, the valence electrons present in sulfur is 6 (see below image).

  • For Fluorine: 

Fluorine is a group 17 element on the periodic table.

Hence, the valence electrons present in fluorine is 7 (see below image).

Hence in a SF5- ion, 

Valence electrons given by Sulfur (S) atom = 6
Valence electrons given by each Fluorine (F) atom = 7
Electron due to -1 charge, 1 more electron is added
So, total number of Valence electrons in SF5- ion = 6 + 7(5) + 1 = 42

Step #2: Select the center atom

While selecting the atom, always put the least electronegative atom at the center. 

(Remember: Fluorine is the most electronegative element on the periodic table and the electronegativity decreases as we move right to left in the periodic table as well as top to bottom in the periodic table).

Here in the SF5 molecule, if we compare the Sulfur atom (S) and Fluorine atom (F), then Sulfur is less electronegative than fluorine.

So, sulfur should be placed in the center and the remaining 5 fluorine atoms will surround it.

step 1

Step #3: Put two electrons between the atoms to represent a chemical bond

Now in the above sketch of SF5 molecule, put the two electrons (i.e electron pair) between each Sulfur atom and fluorine atom to represent a chemical bond between them.

step 2

These pairs of electrons present between the Sulfur (S) and Fluorine (F) atoms form a chemical bond, which bonds the sulfur and fluorine atoms with each other in a SF5 molecule.

Step #4: Complete the octet (or duplet) on outside atoms. If the valence electrons are left, then put the valence electrons pair on the central atom

Don’t worry, I’ll explain!

In the Lewis structure of SF5, the outer atoms are fluorine atoms.

So now, you have to complete the octet on these fluorine atoms (because fluorine requires 8 electrons to have a complete outer shell).

step 3

Now, you can see in the above image that all the fluorine atoms form an octet.

Also, only 40 valence electrons of SF5- ion are used in the above structure.

But there are total 42 valence electrons in SF5- ion (as calculated in step #1).

So the number of electrons left to be kept on the central atom = 42 – 40 = 2.

So let’s keep these two electrons (i.e 1 electron pair) on the central atom.

step 4

Now, let’s move to the next step.

Step #5: Final step – Check the stability of lewis structure by calculating the formal charge on each atom

Now, you have come to the final step and here you have to check the formal charge on sulfur atom (S) as well as each fluorine atom (F).

For that, you need to remember the formula of formal charge;

Formal charge = Valence electrons – Nonbonding electrons – (Bonding electrons)/2

step 5
  • For Sulfur:
    Valence electrons = 6 (as it is in group 16)
    Nonbonding electrons = 2
    Bonding electrons = 10
  • For Fluorine:
    Valence electron = 7 (as it is in group 17)
    Nonbonding electrons = 6
    Bonding electrons = 2
Formal charge=Valence electronsNonbonding electrons(Bonding electrons)/2
S=6210/2=-1
F=762/2=0

Let’s keep these charges on the atoms in the above lewis structure.

step 6

As you can see in the above sketch, there is one -ve charge on the sulfur atom, which indicates the -1 formal charge on the SF5 molecule.

Hence, the above lewis structure of SF5- ion is the stable lewis structure.

Each electron pair (:) in the lewis dot structure of SF5- ion represents the single bond ( | ). So the above lewis dot structure of SF5- ion can also be represented as shown below.

sf5- lewis structure

Related lewis structures for your practice:
Lewis Structure of C2Cl2
Lewis Structure of N2F2
Lewis Structure of CH2
Lewis Structure of HO2-
Lewis Structure of C2HCl 

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